Lubrication Regulator Valve Body Assembly.

TM 9-2520-249-34&P

flows. When the pressure differential is above 40 psi,

degrees off the centerline, pivot steer is available. This

the bypass valve opens, oil from the cooler-in circuit

steering system is also known as "water" steer.

bypasses the cooler and flows directly to the lubrication

(2) In normal steer, the vehicle will "pivot"

regulator valve.

in first and reverse gears--one output will rotate opposite

(2) When the pressure differential is

to the direction of travel while the other output rotates

below 40 psi, the bypass valve remains closed and all

toward the direction of travel.

During steering

oil flow from the converter is directed to the oil cooler.

maneuvers (normal steer) in second, third, or fourth

(The oil cooler is considered as a vehicle component

gear, rotation of only one output is slowed. Thus, the

and is, therefore, described in TM 9-2350230 -35/1.)

vehicle turns toward the side with the slowest rotating

c. Lubrication Regulator Valve Operation.

track.

(3) In pivot steer, the vehicle pivots in

(FO-10). Lubrication regulator valve (80) is a poppet-

every gear except fourth. In fourth gear, the pivot

type, spring-loaded relief valve. All oil from the oil

system automatically reverts to normal steer. The sole

cooler, and that which flows through the cooler bypass

function of pivot valve (63) is to control pressure to the

valve, is delivered to the lubrication regulator valve.

bottom of steer relay valve (75).

This valve maintains lubrication system pressure at 20

d. Drive Relay Valve Operation (FO-12).

psi, supplies oil to the various points in the power train

that require a positive and continuous flow of lubricant,

Drive relay valve (116) determines whether the output

and keeps the fluid velocity governor filled with oil.

clutches are used as driving clutches or whether the

When these requirements are satisfied, the valve directs

reverse or steer clutches will be the driving clutches. In

the excess to the power train sump.

neutral, first, and reverse gears, oil is directed to the

steer relay valve, which, depending on the steer system

being used, sends oil to either the reverse clutches or

2-25.

Bevel Gear Housing.

steer clutches. In second, third, and fourth gears, the

a. Description (FO-5). Bevel gear housing (9)

valve directs oil to the output clutches- regardless of

is an aluminum casting, and it is the largest structural

steer system used.

member. The bevel gear housing is machined to

e. Steer Relay Valve Operation (FO-12).

receive the converter housing, output drive housings,

(1) Steer relay valve (75) determines

bevel drive gear and cross shaft components, brake

whether the reverse clutches or steer clutches will be

coolant pump and top cover assembly.

used as the driving clutches during straight travel, and

b. Function (FO-5). The bevel gear housing

which one of them will be applied during steer. Using

is the main structural member on which all other major

normal steer system for straight travel in first gear, the

assemblies are mounted. It also serves as the oil sump

valve directs pressure to the steer clutches.

for the transmission.

(2) During steer, in first or reverse,

pressure is directed to a reverse clutch and exhausted

2-26.

Covers and Access Openings

from the steer clutch on the same side. In second, third

a. Description.

or fourth gear, no pressure comes from the steer relay

(1) Sump cover (76, FO-11) is an

valve.

aluminum casting or steel stamping, located at the

(3) During steer in first, second or third

bottom center of the bevel gear housing. Sixteen bolts

gear, with the pivot steer system in use, the valve

(79) attach the cover to the bevel gear housing.

directs pressure to a reverse clutch and exhausts the

Magnetic drain plug (81) is located in the center of the

driving clutch on the same side. In fourth gear, the pivot

cover.

steer system automatically reverts to normal steer-no oil

(2) Housing cover assembly (36, FO-13)

pressure is sent to the reverse clutch.

is an aluminum casting that covers the top opening in

the bevel gear housing. The cover assembly is attached

2-24.

Lubrication Regulator Valve Body Assembly.

to the bevel gear housing by 14 screws (31). Other

a. General Description (FO-10). Lubrication

bolts used to attach adjacent components also retain the

regulator valve body assembly (73) is bolted to a

cover assembly. Numerous passages are machined or

mounting pad located on the lower right side of the

drilled in this cover for distribution of oil.

converter housing. Two valves, lubrication regulator

(3) Right and left brake adjustment covers

valve (80) and cooler bypass valve ball (77), are

(24 and 40) are located on housing cover assembly (36).

contained within valve body (84).

These small covers are each retained by five capscrews

b. Cooler Bypass Valve Operation (FO-10).

(27, 28, 43 and 44).

(1) The cooler bypass valve is a spring-

(4) Right and left end covers are located

loaded ball (77), that is actuated by a 40 psi pressure

on the output drive housings.

differential between the cooler-in and cooler-out.

2-10